1. Field of the Invention
This invention relates generally to a signal recording apparatus having at least one rotary magnetic head, and more particularly is directed to a signal recording apparatus particularly suited to serve as a slave recording device in a magnetic tape recording system of the type that employs a single master tape player providing a signal to be simultaneously recorded on a plurality of magnetic record tapes by a plurality of slave recording devices.
2. Description of the Prior Art
When it is desired to provide a number of copies of a magnetic tape having video, audio or other information signals recorded in slant tracks thereon, the signal to be recorded is reproduced by a master tape player and supplied simultaneously to a plurality of slave recording devices in which copying in real time is effected. The foregoing procedure is quite obviously costly and time consuming in that a period of time equal to the duration of the original recording is required for producing each copy thereof. In a magnetic transfer-type copying system, high-speed dubbing can be performed, for example, at a speed 120 times the ordinary recording speed. In such case, in an intermediate stage of the process, it is necessary to form mirror images of the original track pattern on blank tapes, and for this purpose a plurality of mirror image slave recorders are connected to a single master player, and simultaneous recording is performed in real time in order to obtain a plurality of mirror image tapes which can each be used in the magnetic transfer-type copying or dubbing system. A mirror image recorder of the foregoing type is known, for example, as disclosed in Japanese Patent Publication No. 48-30886, or in U.S. Pat. No. 3,592,977.
However, when a plurality of slave recorders, such as, the above mentioned mirror image recorders, are operated simultaneously, it is difficult to achieve precise synchronization of the slave recorders with the master player. More specifically, even when the master player and the slave recorders are operated in response to a common sync or external reference signal, the individual slave recorders have a jitter or residual servo error inherent in the respective rotary head servo systems. By reason of such jitter or residual servo error in the rotary head servo system of a slave recorder, the end edges T.sub.e of the successive slant tracks T in which the signal is recorded on the magnetic tape 7 are not properly aligned, that is, the end edges T.sub.e are not uniformly spaced from the side edge of the tape, but rather are irregularly stepped as shown in FIG. 4A. When a mirror image tape having improperly aligned track patterns, as in FIG. 4A, is employed in a magnetic transfer-type copying system providing high-speed dubbing, the resulting copy tape sometimes cannot be reproduced or played back, especially when digital data, such as, digital audio signals, are used as the source of the signals recorded in the slant tracks on the tape.
When only a single slave recorder is connected to a master player a reference pulse provided by a reference pulse generator so as to represent the rotational phase of the rotary magnetic head of the single slave recorder is fed back to the master player, and the supplying of the data or signal to be recorded from the master player to the slave recorder is effected in synchronism with such reference pulse. In other word,, in the case of a single slave recorder associated with a master player, the rotary magnetic head of the master player can be maintained precisely in a predetermined phase relation to the rotary magnetic head of the single slave recorder so that the end edges of the slant tracks recorded by the slave recorder can be maintained in alignment, that is, uniformly stepped in succession. However, when a plurality of slave recorders are connected to a single master player, there may be phase differences between the reference pulses generated by the several slave recorders, by reason of the previously mentioned jitter or residual servo error inherent in each of the slave recorders, with the result that it is difficult to achieve the precise synchronization of the single master player with all of the plurality of slave recorders.